1. Field of the Invention
The present invention relates to a method and apparatus for improving the fuel efficiency of an internal combustion engine, and specifically to a method and apparatus to minimize, reduce and lower the operational combustion engine compartment temperature to maintain relatively low intake air temperature in order to achieve improved combustion engine efficiency and reduced fuel consumption without reducing engine performance.
2. Description of Related Art
Internal combustion engines are used to power vehicles such as cars and trucks. Internal combustion engines utilize air and fuel to create a combustion charge which is burned to create rotary movement of a crank shaft. The rotation of the crank shaft is used to propel the vehicle and power other systems on the vehicle.
An internal combustion engine generally includes an engine block having at least one combustion chamber, an air intake port, an air intake manifold connected to the air intake port and an exhaust port connected to an exhaust manifold. Air is fed to the air intake manifold by an intake plenum. Air is mixed with fuel creating a charge within the intake manifold which is drawn into the engine block by the expansion of a combustion chamber. The charge is compressed and burned by the combustion chamber. The products of the burned charge are released from the engine block through the exhaust port and travel through the exhaust manifold which is normally connected to a muffler.
When used to power a car or truck, the combustion engine is normally located towards the front of the car or truck within an engine compartment formed by an engine bay which is covered by a hood. The combustion of fuel within an engine block (which is iron or aluminum) creates a large amount of heat which is conducted and radiated within the engine compartment. This heat productivity causes the intake manifold and intake plenum in the engine compartment to be continuously heated which increases the temperature of the intake air delivered to the engine, reducing engine gasoline and diesel fuel efficiency.
Some engines used to power cars or trucks utilize turbochargers. Turbochargers use the velocity of the exhaust gases expelled from the engine block to rotate a compressor which compresses the intake air delivered to the intake manifold above atmospheric pressure. The pressurized air allows the engine to operate more efficiently by providing a charge with increased density. Turbochargers by their nature create additional radiant heat energy within the engine compartment by providing an increased surface area for exhaust heat to emanate and increasing the time the exhaust gases spend within the engine compartment as they are forced to follow a longer path in order to turn a compressor.
It is known to attempt to reduce the temperature in the engine compartment to allow a person to work on an engine while the engine is running without subjecting the person to the dangers of being burned. Some areas of an engine compartment are covered by heat protectors to reduce the heat that radiates from the engine.
The present invention is especially useful in a large truck diesel engine to greatly improve fuel efficiency by significantly reducing the temperature of the ambient air within the engine compartment by insulating heat producing components as well as the intake plenum.
Prior art methods of decreasing the heat generated within the engine compartment include insulating wraps which are wrapped around exhaust headers such as those manufactured by Design Engineering, Inc. and Cool It Thermo Tec. These wraps are formed by high temperature fiber wraps which are used to insulate exhaust headers. These wraps are applied to an exhaust header by wrapping them around the tubes that comprise the header and securing it in such fashion with clamps. Additionally, those conventional wraps are designed to prevent radiant heat from escaping rather than preventing radiant heat from entering.
What is needed is a method and a system for thermally insulating both conductive and radiant heat generating engine parts including turbochargers and exhaust headers to reduce the heat radiated within the engine compartment. Also the intake air box and intake air plenums are covered with thermal insulation to reduce the heating of the intake air delivered to the engine so that the overall efficiency of the engine is increased. The present invention provides a system for reducing conductive and radiant heat generated within the engine compartment and to reduce the temperature of the intake air delivered to the engine via the intake air box and intake plenum.
A method and system for increasing diesel combustion engine efficiency and reducing fuel consumption in a large truck diesel engine with a turbocharger that includes lowering intake air temperatures by reducing engine compartment heating. The exhaust manifold is covered with thermal insulation layers forming a thermal shield to reduce engine compartment heat. The turbocharger compressor and turbine are both covered with thermal insulation layers except for the bearing location to reduce engine compartment heat, the intake air box and intake plenum are covered with a light weight reflective insulation to prevent heating of the intake air. The engine compartment hood is also insulated to prevent heat build up that would cause increased compartment heating. By insulating many components that produce and radiate heat, the overall efficiency of an engine can be greatly increased by reducing the heating of the intake air.
Exhaust manifold multi-layered thermo shields are used to thermally insulate the exhaust manifold to reduce the heat radiated from the exhaust manifold into the engine compartment. The shield is wrapped around the exhaust manifold so that most of the manifold is insulated. The heat insulating and radiating materials used to cover the exhaust manifold include a thermal insulating layer of manning glass, a thermal insulating layer of heavy stevens cloth, a wire mesh layer adjacent the stevens cloth to prevent cloth wear, and a top layer of a heat reflecting fabric such as aluminum coated fibers known as GENETEX to reflect engine compartment heat. The layered insulating materials form a laminate insulating shield that is cut and shaped to effectively cover thermally the exhaust manifold to reduce engine compartment heat while being a relatively light weight shield that is resilient and flexible enough to be shaped about the top of the manifold headers and held firmly in place by wires or safety straps.
The turbocharger is insulated with a thermal insulation shield of the same materials as the exhaust manifold above also using individual layers of manning glass and stevens cloth. A wire mesh layer is also used to prevent wear on the insulation from vibration. The outer layer is also an aluminum fabric known as GENETEX that reflects heat. Since the turbocharger compressor is somewhat cylindrical, the insulating layered shield is cylindrical to fit substantially around and over the compressor secured by peripheral wires. The turbine housing of the turbocharger is likewise covered with the same thermal insulation materials as the exhaust manifold and secured by peripheral wires. However the external area of the turbine housing near the bearings is not covered to protect the bearings from overheating. The insulation shield is held in place by wire ties. Thus, two separate thermo shields are used on the turbocharger.
The hood is insulated with a layer of manning glass and a layer of planar aluminum foil that is fixed by adhesive to the hood surface.
The air intake passage and air intake plenum are thermally insulated with a layer of manning glass and an outside layer of aluminum foil which is affixed by an adhesive to the outside housing of the passages and plenum.
The fuel lines are insulated to reduce the heat that they absorb to prevent fuel vapor lock.
By greatly reducing the ambient and radiated heat built up within the engine compartment, the heating of the intake air is significantly reduced relative to the traditional temperatures present from engine compartment heat, greatly improving fuel efficiency and reducing fuel consumption. Reducing the temperature of the intake air increases engine efficiency. Reducing the radiant heat within the engine compartment and insulating fuel lines also eliminates the potential for vapor lock which is caused by the heating and subsequent boiling of fuel within the fuel lines.
Fifteen to twenty percent savings in fuel consumption has been achieved on Detroit Diesel Truck Series 60 engines using the method and system of the present invention.
In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings.